Configuring DHCP Scopes

This section shows you how to perform specific actions in Micetro associated with maintaining your DHCP scopes, such as creating and modifying reservations, setting scope options, and working with split scopes.

Note

For informatin about how to create scopes, see Networks.

Managing DHCP Pools

A DHCP pool is a range of IP addresses that the DHCP server can assign to clients. Each pool is defined within a specific subnet. You can configure the IP address ranges that a DHCP server can assign to clients on a network.

Adding an Address Pool

  1. Select the relevant scope for which you want to create an address pool.

  2. On the Action or the Row … menu, select Manage DHCP pools.

  3. Click Add pool.

  1. In the Add pool dialog box, enter the range of addresses to be included in the pool in the From and To fields. These fields default to the first available address in the range. If this scope is shared across multiple servers (a split scope) and there is an overlap in the address pool, a warning message will appear.

  2. Click Add.

Editing and Removing Address Pools

To edit or remove an existing address pool:

  1. In the Manage DHCP pools dialog box, select the relevant pool.

  2. On the pool’s row … menu, select Edit to modify the pool or Remove to delete it.

Editing DHCP Options

Note

DHCPv4 and DHCPv6 scopes inherit DHCP and DDNS Options from the parent DHCP server. DHCPv4 and DHCPv6 reservation inherit DHCP and DDNS options from the DHCP scope. However, these options may be changed by editing the options for the specific scope or reservation.

Viewing the configured DHCP options for a DHCP scope:

  1. Select the DHCP scope in the networks list.

  2. On the Action or the Row … menu, select Edit scope options.

  3. A dialog box is displayed. Note that in order to see the options that have inherited values, you need to select the Show inherited options checkbox.

Adding a New DHCP Option

To add a new DHCP option:

  1. Start typing into the Add an option field. You can enter either the name of the option or the its number.

  2. As you type, a list of available options will appear.

  1. Select the option you want to add.

  2. The selected option now appears in the list and you can assign values to it.

HEX and ASCII Representation

Certain DHCP options, such as DHCP option 43 (Vendor Specific Info), require the value to be in HEX format. In such cases, the user interface allows the value to be displayed in both HEX and ASCII format by selecting the appropriate tabs above the input field.

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Removing a DHCP Option

To remove a DHCP option, hovering over the desired option in the Edit Scope Options dialog box. A trash can icon will appear to the right of the option. Click this icon to remove the option.

Deleting a Lease

You may need to delete a lease from a DHCP scope, such as when a device is no longer in use or needs to be reconfigured. When a lease is deleted, the IP address associated with that lease becomes available for reassignment by the DHCP server.

To delete a lease in a DHCP scope:

  1. Open the scope containing the lease you want to delete.

  2. Select the lease and select Release DHCP lease on either the Action or the Row … menu.

Creating DHCP Reservations

DHCP reservations can be created in unassigned address spaces, address pools, and excluded addresses. You can also set specific options for reserved IP addresses.

To create a reservation:

  1. On the Networks tab within the IPAM page, select the relevant scope.

  2. Open the scope by clicking Open on the top toolbar or by double-clicking it.

  3. Select the relevant IP address and click Reserve on the top toolbar.

  4. Fill in the necessary information.

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  • Name: Assign a name to identify the reserved address.

  • Reservation method: Choose between Hardware address or :guilabl:`Client identifier`.

    • Hardware address: Enter the MAC Address (Media Access Control Address) of the network node for which this address is being reserved.

    • Client identifier: Use the Ascii and Hex switch on the right to change the input type.

  • Reservation type: Select whether this reservation should support DHCP, BOOTP (Bootstrap Protocol), or both (default).

  • Description: (Optional) Provide a description.

  1. Click Create to finalize the reservation. The IP address will receive the status Reserved.

Editing and Deleting Reservations

To edit or delete a reservation:

  1. Select the reserved IP address.

  2. On the Action or the row … menu, select Edit DHCP reservation to modify the reversion or Delete Reservation(s) to delete it.

Editing Reservation Options

To edit reservation options:

  1. Select the reserved IP address.

  2. On the Action or the row … menu, select Edit reservation options. For more information about DHCP options, see Editing DHCP Options.

Adding Exclusions (MS DHCP only)

You can exclude a single IP Address or an entire range of addresses from being used. Exclusions can only be made for addresses that are already part of an existing address pool.

To create an exclusion:

  1. Select the relevant scope.

  2. On the Action or the Row … menu, select Manage DHCP pools .

  3. Click Add exclusion.

  1. In the Add exclusion dialog box, enter the range of addresses to be excluded in the From and To fields. All addresses within this range, including the start and end addresses, will be excluded.

Editing and Removing Exclusions

To edit or remove an existing exclusion:

  1. In the Manage DHCP pools dialog box, select the exclusion you want to edit or remove.

  2. On the exclusion’s row … menu, select Edit to modify the exclusion or Remove to delete it.

Managing DHCPv6 Exclusions

You can create an exclusion range within a DHCPv6 scope to prevent the DHCP server from assigning IP addresses within that range. This allows you to manually assign those addresses without conflicts. When managing exclusions within a DHCPv6 pool, you have the option to specify a percentage of the DHCPv6 scope instead of manually entering the From address and From address.

To add an exclusion:

  1. Select the desired DHCP scope.

  2. On the Action or the row … menu, select Manage DHCP Exclusions.

  3. Click Add Exclusion.

  4. In the Add exclusion dialog box, choose to create the exclusion range by either Percentage or Manual entry:

  • Percentage: Drag the percentage bar to the correct percentage of addresses you’d like to exclude and enter a From address only.

  • Manual entry: Enter the From address and From address for the range you’d like to exclude from the DHCP scope.

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Note

If the exclusion range doesn’t have the space to accommodate the specified percentage of IP addresses, it will not allow you to add this exclusion range. Adjust the From address or lower the percentage as needed.

  1. Click Add.

  • Red bar: Represents the exclusion range.

  • Blue bar: Represents the address pool of dynamic allocation addresses.

Reconciling Scopes

Note

Applies to Microsoft DHCP servers only.

Reconciling scopes is a crucial task to ensure the consistency and reliability of your DHCP configuration. This function is specifically applicable to Microsoft DHCP servers and is used to address inconsistencies between the information stored in the Windows registry and the DHCP database. Such inconsistencies can cause issues with IP address allocation and network stability. Use this function to fix inconsistencies between information in the registry and the DHCP database.

To reconcile DHCP scopes:

  1. On the Networks tab on the IPAM page, select one or multiple DHCP Scopes from Microsoft servers.

  2. On the Action or the row … menu, select Reconcile DHCP Scopes.

  3. If any inconsistencies are found, a list will be presented. Click Fix to resolve the inconsistencies.

For more detailed information, see the Microsoft documentation.

Split Scopes

Note

Split scopes are only supported on MS DHCP and ISC Kea servers.

Split Scopes in Load Balancing Mode

When creating scopes on Kea servers configured in load balancing mode for high availability, Micetro will evenly split the available pool between primary and secondary servers. This ensures efficient distribution of IP addresses and enhances network reliability by balancing the load and providing redundancy.

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Managing Split Scopes for DHCPv6

A split scope divides the DHCP address range into two or more segments, with each segment being assigned to a different DHCP server. This ensures that if one server fails, another server can continue providing IP addresses to clients.

To manage DHCPv6 split scopes:

  1. On the Networks tab on the IPAM page, select the relevant DHCPv6 scope.

  2. On the Action or the row … menu, select Manage scope instances.

  3. Select a second server to manage the DHCP scope, and then click Add. Enable the servers on which the split scope should reside.

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Note

You can change the server preferences by clicking and dragging the hamburger icon (the three lines to the left of the server) to change the server order. The preference for the second server will always be the First Server Preference + 1, and each additional server will increment by 1.

  1. Click Save.

  2. On the same scope, select Manage DHCP Exclusions` on either the Action or the row … menu.

  3. Click Add Exclusion for the first server. Select the percentage of the address range you want to exclude from the first server and click Add.`

  4. Click Add Exclusion for the second server. Select the address range you want to exclude from the second server and click Add.

  1. Click Save.

Enabling or Disabling Scopes

If a scope is no longer needed but you want to keep it for potential future use, you can disable it instead of deleting it. When a scope is disabled, it will be ignored by the DHCP server until it is re-enabled.

To enable or disable a scope:

  1. Select the scope you want to enable or disable.

  2. Select Disable scope or Enable scope on either the Action or the Row … menu.

  3. Click Yes to confirm.